JimmyT

I'm considering a set of track wheels & tires for DE use for a base boxster. Here is what my (reasonably close size) options appear to be. All would be mounted on OZ alleggerita 8x18 and 9x18:

Stock size - only option:
Bridgestone RE-11.
235-40-18 25.4" dia
265-40-18 26.3" dia
dia ratio = 1.031

In alternate sizing I see these options:

Direzza star spec
225-44-18 25.1"
275-35-18 25.6"
dia ratio = 1.02 is close to stock and car would be lowered about 0.35" front and rear. This could be great as it also lowers gearing about 3%.

I could get nearly the same effect of reducing overall diameter slightly, but keeping F/R dia ratio by doing this:

Kumho Ecsta XS
245-35-18 24.8"
275-35-18 25.6"
dia ratio = 1.032 Again slight lowering of car and gear ratio. Perfect dia ratio.

Also, could go with either of these:
Advan A048 (rcomp)
225-40-18 25.0"
265-35-18 25.2"
dia ratio 1.01. This is matched closer F/R diameter, but would also lower the car a bit. Drawbacks are narrower front, and rear diameter a little on the small side.

Toyo R888 (rcomp)
235-40-18 25.3"
275-35-18 25.7"
dia ratio 1.016. This is a slightly better option than Yok's.

I assume that any options of 235-40-18 with 265-35-18 are a bad fit as there is no F/R diameter stagger. This is the size combo that seems to be most widely available. Here is what I want your feedback on:

1) I don't mind the idea of a little smaller overall dia, as it will lower the car just a bit, reduce gearing a bit, reduce unsprung weight and moment arm.

2) I think I should try to keep the F/R ratio about stock, which will lower both ends about the same. Not doing this can fool electronic gadgets and mess with balance of car.

3)If using these set ups for driving to/from track and DE weekends will the R comps be noticibly better on track?

4) will they wear noticibly faster than the no R comps? I will get about -1.0 front camber on my car, but I'm worried about outside wear, and wonder if R comps might be more durable in this regard and the tread is more solid and handles heat better.

Thanks in advance for sharing your expertise.

Jim

00r101

Yes they will wear faster. How much depends on your driving style. The height differences don't mean squat. I would get the Dunlops but in these sizes 245/275 the extra width in the front is important for more neutral handling. The height diff from stock won't matter. It won't screw with the ABS. The extra tip up to the front won't matter. How do i know? I have been running that setup on the street for almost a year now and I love it. The Toyos are also a good choice, everyone likes their wet performance on track as well as their ability to work better when hot.

brad@tirerack.com

Jimmy, please give me a call and we'll pick you something out based on your needs.

Thanks.

n2cars

Damon,
Is there an R compound tire for the Boxster Spyder?
235/35 ZR19
265/35 ZR19

drcollie

There's a HUGE difference on R-Compound tires at the track, especially when braking. You cannot use Porsche brakes to their fullest on street compound tires. If you're serious about being a track junkie, don't use 18" wheels, go to 17's, because the R-Compounds are much less expensive in that size. You have "x" number of heat cycles in an R-Compound tire, so you really don't want to drive to the track on them, better to haul them if at all possible (see the slippery slope? Car Trailer, Tow Vehicle, etc.). With every heat cycle, they lose a little 'stick'. When you see them having a bluish-gray cast to the tire, they're used up. Most the time you will use up the heat cycles instead of wearing them out.

They also are more prone to flat tires on the street, and you don't even want to run R-compounds with a plug or patch in them (speed rating is compromised and eliminated with any repair) - pick up a nail and the tire is dead. Run a set of old nasty wheels at the track, as long as they are round and true, that's all that matters - they'll be black from brake dust in three laps anyways.

I know, I know....there are guys that think its cool to run R-Compounds on the street. Hey, that's fine if you want to feel like you're a race car driver, but in truth they're noisy, don't work well when cold, have the aforementioned affinity for nails, and will burn up a lot of cash with the quicker wear.

I'm been going to the track since 1995, and tried it all the various ways, eventually only going with a tow rig after prepping the car the night before with wheel swaps and brake pad changes. If you can't do the tow rig, then a small trailer that holds four tires and wheels behind the car is viable if you can stand the thought of a trailer hitch on the Boxster.

JimmyT

So I'm sort of leaning toward the Kumhos in 245-35 and 275-35. Anybody seen sizes like this on a boxster? I'm wondering if I'll hate the way they look as the diameter is about .7" smaller than stock both F/R. Side benefit would be a subtle benefit to this route in ever so slightly lower gearing, unsprung weight, and ride height. These will be track weekend only tires.

Hard to find really good non r comp track tires for this car in the right size. RE-11 is the only stock size, and only a few offer 245-40 and 275-40, but that goes the opposite direction to the advantages I mentioned above.

Thanks for the feedback.

Jim

00r101

If you are worried about the looks of your tires maybe you want to avoid track driving.

JimmyT

Good point.

drcollie

17" tires and wheels will also be faster than 18" or 19" wheels and tires. Why? Quite simply, they weigh less. Less unsprung weight means better handling and a higher top speed, they also don't have the aerodynamic drag of the larger wheels. Hate to tell you this, but larger wheel/tires are for show/bling, not performance - at least not on a car pushing less than 300 HP/3,000 lb. Add that to the cheap cost of take off wheels and overall tire cost and its a no-brainer.

If you're going to the track to look pretty, then keep your car in the parking lot and you can wipe it down with Mequires Quik Detailer every few hours.

sjfehr

If I might add... big wheels and thin tires help with the "supercar" look, but supercars have to put on massive wheels to clear their massive brakes, and need thin tires to compensate to keep the same overall diameter. Use of the bigger wheels is a performance-reducing compromise, not something to be desired in a performance car.

BTW, (and I think I speak for all tech inspectors here), PLEASE lay off the tire shine on your tires! I don't want that **** all over my hands when I'm checking your tires and wheel bearings.

JimmyT

I'm not going to the track to look pretty. I want to be the best driver. I didn't say fastest, because I'm not racing, and I want to be within my limits. I want to know that if I decided to race, I could beat you in my car, then take your car and beat you again. Familiar personality type around here, I think.

I'm afraid things have taken a turn that I didn't intend and we're getting off topic, so let me clarify a few things.

I expect I'll end up with the OZ Allegerita wheels for the track. I decided that for three reasons:

1) I looked into 17" wheels for exactly the reasons that have been brought up. Lighter, cheaper, more tires available, tires cheaper, don't care as much about the look at the track. Stock boxster 17's are plentiful and cheap, unfortunately, they are also too narrow to be very useful.

2) A set of take off 18" boxster wheels isn't going to be much cheaper than OZ's, becasue they are not in plentiful supply. They are the wheels people want, not the wheels people are taking off.

3) The OZ's are almost 4 lbs per wheel lighter than the stock 18's, and good wheels don't seem to be available in 17. I actually checked that and had ruled out 17" sizes before posting here, but I was really considering 17's before I found out how limited the wheel availability is.

With all that said, the reason I ended up posing my question is that there is literally ONE non r comp tire avaiable in my stock 18" size that's better than the RE050A's that I run on the street. I just wanted to understand the pro's and con's of other tires that could be found in potentially acceptable non stock dimensions.

Thanks for sharing your knowledge.

Jim

racer

Before you jump down expensive tire/wheel upgrades... How much Track experience does the Original Poster have to begin with?


As many have already been through, you might do yourself more justice in the "learning to drive" catagory by focusing on track time, even if it means not running optimal tires. If you are afraid to drift the car through a high speed bend on street tires, how will you handle it going 10mph faster on "R" comps?

imho, from my Boxster days, a 225/275 combo resulted in understeer more often than desired. A 275 is fine in the back, but I would match it to a 245 up front..

JimmyT

Very little, and I want to get a lot more, which is why I want to get a set of track tires that I can wear out and save my stock wheels and street tires from getting beat up and some tread to drive in the rain. It's not a performance issue. (Well it is... but for the street)

racer

Then get whatever is cheaper.. you will go through them quickly anyway. Don't jump on the Rcomp bandwagen until you can understand what the car is doing and how to control it. And get yourself to some local Autocross events which will help you learn the car (seat time) for little money ($30-40 an event). There will be plenty of chances to spend your money on you and your car as your driving experience grows.

While I have only used Toyou RA-1s the past 5 years, from your list above, the Dunrocks (sorry, Dunlops) or the Bridgestones seem like good choices.

Tbred911

go michelin PS2 for the track... its a great tire to learn on... just make sure you find the right pressures "hot" and use a quality pressure gauge because there are lots of bad ones out there...